This invention was the subject matter of Document Disclosure Program Registration No. 221581 which was filed in the U.S. Patent and Trademark Office on Mar. 6, 1989.
As can be seen by reference to the following U.S. Pat. Nos.: 3,554,321; 4,143,742; 4,607,726; and 2,969,126; the prior art is replete with myriad and diverse ladder extension apparatus that are intended to level a ladder on an uneven surface.
While all of the aforementioned prior art constructions are more than adequate for the basic purpose and function for which they have been specifically designed, these devices are also limited in their basic design in that they fall into one of two categories. The most common category being the plural legal adjustment variety wherein both legs of the ladder can be adjusted independently; and the other category being the single leg exterior mounted variety wherein a detachable adjustment mechanism can be mounted on the outboard surface of either of the legs of the ladder.
In the first instance the plural leg adjustment devices are very costly to incorporate into the ladder structure, and usually contain a large number of components which are subject to structural failure which will render the ladder inoperative for uneven surfaces.
In the second instance the single leg variety is typically mounted on the outboard surface of the ladder legs which of necessity extends the width of the ladder, and the outwardly projecting portions of the adjustment mechanism tend to bump into movable and stationary surfaces as the ladder is being moved to and from a job site.
Furthermore there are certain instances wherein the standard width of a ladder is unsuitable for either variety of adjustment mechanism due to the narrowness and/or uneven contour of the workplace.
As a consequence of the foregoing situation there has existed a longstanding need for a new type of ladder adjustment mechanism that will overcome the shortcomings of the prior art constructions and provide a ladder adjustment device that is both adjustable and laterally translatable relative to the rung of a ladder. The provision of such a construction is a stated objective of the present invention.